1/17There are not too many junkyard motors besides the 5.0L Ford that can handle the combination of a blower, heads, and a hydraulic roller cam and pump out over 600 hp on pump gas. Somewhere, Henry smiled.

'There are a number of a good reasons that the old pushrod 5.0L Ford engine is so popular with car crafters. On a good day you can buy a used motor without the EFI for less than $200. The '85 and later Mustang engines come with forged pistons, the engine has an outstanding bore-to-stroke configuration, and the '86 and later packages come with a hydraulic roller cam. Add this all up and it makes for a great foundation for a V-8 power combo. A couple of years ago, Glad tripped over a wrecked Mustang GT for $700, equipped with a 5.0L engine that will eventually find a home in our '67 road racer Mustang. But first, we decided to see how much power we could push through this little 302ci Ford. The plan was classic Car Craft. We'd baseline the engine with a carburetor, stuff a centrifugal blower on it, and praise whatever survived. But because we're powermongers, we decided that was too easy. So we decided to add a set of heads and a bigger cam for more naturally aspirated gusto and then jam the blower on top of that for the ultimate power statement. True to its Blue Oval heritage, our little 20-year-old Ford proved itself gutsy enough to make 392 hp normally aspirated and a criminal 605 big ones with the blower. Those are the peak numbers, but equally impressive lessons were in how we got there. It was the perfect victimless crime.

The BackstoryLike any good junkyard revival, this 5.0L Ford ended its first life when its previous owner tested the laws of physics by trying to move a large tree with his '88 Mustang. The Fox-bodied Ford lost the contest, and we picked up the pieces. The beauty of this purchase was that we scored not only a complete engine with its EFI intact, but also the AOD trans and a 2.73-geared 8.8 rearend that we swapped into our '67 Mustang. So we started with a used but healthy 302ci small-block with its advertised 9.0:1 compression ratio, tiny iron heads with 1.74/1.46-inch valves, and an equally mild stock hydraulic roller cam with barely 0.440 inch of lift. Previously, this engine had participated in a flat-tappet cam test that ended unexpectedly, but it came out of it with a set of screw-in studs, guideplates, good valvesprings, and a set of Comp 1.6:1 Magnum roller-tipped rocker arms. While this may have played a small part in the overall-stock engine's power curve, it's likely that these parts did little more than just improve durability. For induction purposes, we canned the EFI and went with an Edelbrock Performer RPM dual-plane, a Barry Grant Speed Demon 650-cfm carburetor, and a set of Westech's dyno 131/44-inch headers with no mufflers. Finally, we enlisted an MSD Ford billet distributor fitted with the proper gear to run against the factory steel hydraulic roller cam gear. We used this same distributor throughout the entire dyno test since the Comp hydraulic roller cam also uses a hard-steel gear.

Oil and Water Don't MixOur dyno session with Steve Brul at Westech was not without its self-inflicted damage. Once the engine was on the dyno, the initial warm-up produced a projectile-vomited spray of milky spooge out the breather tube when the engine filled up with water from a poor intake-manifold seal. The cleanup and postmortem took an hour, and we were careful to install new Fel-Pro intake gaskets and religiously torque the bolts in proper sequence. When the engine gushed the second time, we decided to swap intake manifolds along with a third set of gaskets. This time we were successful.

While it would have been easy to blame the gaskets, in our case it appeared there was a slight misalignment of the intake to the cylinder head that caused the first intake to be open toward the bottom of the interface between the intake manifold and the head. This angular mismatch allowed water into the lifter valley, creating that nasty milkshake that probably qualifies Westech as an environmental hazard site now. We also learned that ARP makes intake-manifold studs for the small-block Ford that will help seal the intake to the heads more efficiently, and we've included that part number in our parts list. But the most important lesson learned was to not ignore the angle between the intake-manifold face and the head on a small-block Ford, because the bolts pull down at a different angle to the manifold sealing surface. Place the intake on the head without the gaskets and closely inspect the angle of the manifold face relative to the head. If the angles are not parallel, there's a good chance it will leak.

6/17The P-1SC ProCharger is rated to deliver up to 825 hp, which is probably why 600 hp from our 302 was so effortless. The only thing easier than making the power was bolting on the blower.

The BlowerThis whole story started with a simple question at a Car Craft staff meeting. "How much power do you think we could make by bolting a centrifugal blower on a bone-stock small-block?" In this case, we estimated that if the additional cylinder pressure from the blower didn't lift the stock heads off the deck, we might make 350 hp if we were lucky. We began our quest for a supercharger by talking with our friends Bob and Terry Woods at The Supercharger Store in Huachuca City, Arizona. It is an ATI ProCharger dealer, and several discussions led to a P-1SC centrifugal, which is one of ProCharger's entry-level superchargers. The SC tag stands for self-contained, which means the supercharger does not rely on engine oil for lubrication, instead housing 6 ounces of ATI special sauce to lubricate its internal machinations. ATI rates this blower at up to 825 hp and intended for normally aspirated engines making between 200 and 500 hp. The supercharger is rated for a maximum of 1,200 cfm and as much as 30 psi of boost. Our approach was far more sedate, reaching for around 10 psi, but it did attain right at a 50 percent power increase on both applications.

The truth of the matter is that we started off with a pretty decent little 302ci baseline at 270 hp (compared to Ford's original horsepower rating of 225) with help from the Edelbrock RPM intake, Speed Demon 650-cfm carburetor, and 131/44-inch open headers. This solid baseline bumped our estimate to 380 hp, so we were pleasantly surprised by the 408 peak horsepower number the 5.0 generated at 5,400 rpm. Torque is what moves the car, and with never more than 10 psi of boost, the blower still added between 60 and 136 lb-ft of torque from 3,400 rpm up.

One of the more surprising aspects of the ProCharger was how easy it was to install. The ATI-supplied three 71/416-inch bolts mounted the blower bracket to the driver-side cylinder head. We then bolted the blower to the bracket and the lower pulley to the crank. It took only a few minutes to line up the 3-inch outlet hoses between the blower and the carburetor hat, and a few minutes more to stretch the eight-rib serpentine belt over the pulleys and set the tension, and we were ready. Granted, that was working on the engine out of the car. But it would only take a few more minutes than that in the vehicle. This ProCharger was easier to bolt on than any nitrous system we've ever installed.

Heads And Cam PackageWe decided to try the Racing Head Service (RHS) 180cc aluminum small-block Ford heads on our little 302 because we had heard good things from our Ford buddies about them. Right away we were impressed when we bolted one up on the SuperFlow 600 flow bench and watched as the as-cast intake port generated 249 cfm at 0.500 lift and 255 at 0.600 inch of valve lift. With solid midlift intake flow numbers and good exhaust-to-intake flow data, the heads looked promising. Combined with a Comp Cams hydraulic roller with 0.550-plus lift, they promised good power. Even better, the compression jumped from a stock 8.85:1 to 9.5:1 with the RHS 58cc combustion chambers.

We had to swap in stronger valvesprings because the heads we ordered did not come with sufficient spring pressure to handle both the rigors of higher engine speeds and the demands the blower would place on the back side of the intake valve. Using Brul's recommendation of 200 pounds of load on the seat at the installed height of 1.800 inches and 400 pounds across the nose at max lift, we opted for a set of Comp springs that both fit the head perfectly and also produced the load necessary to keep the valvetrain together at the engine speeds we knew were imminent.

CAM SPECS

Camshaft

Duration

Duration

Lift

Lobe

(Adv.)

(@ 0.050)

(in.)

Separation

Stock Ford cam, int.

266

- - -

0.445

115

Hydraulic roller, exh.

266

- - -

0.445

XE274HR-12, int.

274

224

0.555

112

XE274HR-12, exh.

282

232

0.565

14/17We also had to drill and tap the accessory bolt holes in the front of the head to bolt on the supercharger, since the RHS holes were only 31/48 inch and needed to be 71/416 inch.

*This boost pressure curve was generated on Test 4. The curve on Test 2 was roughly 0.5 psi higher over the entire rpm curve due to the greater restriction of the stock heads and cam. When we added race gas and more timing, the boost jumped to 12 psi.

FLOW CHART

Valve lift

Intake

Exhaust (no pipe)

E/I

0.{{{100}}}

63

44

69%

0.{{{200}}}

118

97

82%

0.{{{300}}}

172

133

77%

0.400

223

159

71%

0.500

249

169

67%

0.{{{600}}}

255

174

68%

0.700

266

177 66%

16/17

This head was tested on a 4.030-inch bore fixture at 28 inches of test depression.

Flow TestingThe intake flow numbers are impressive, especially with 249 cfm at 0.500 inch of valve lift. It's also important not to overlook the exhaust side. Stock Ford heads are notorious for their weak exhaust ports, so it's clear that RHS placed extra effort toward improving exhaust flow. This not only helps at higher engine speeds for normally aspirated horsepower, but is also a key factor in how this little 302 was able to make over 600 hp. Also note how well this exhaust port flows at low valve lifts like 0.200 inch with an exhaust-to-intake (E/I) flow relationship of 82 percent of the intake. Superior low-lift exhaust flow does a better job of scavenging exhaust gas out of the cylinder, which means less residual exhaust gas in the cylinder during the next intake stroke.

17/17

Dyno Testing Right out of the gate, this little junkyard refugee ran some pretty decent numbers with 273 hp and 319 lb-ft of torque. The guys at the Supercharger store told us to expect at least a 42 percent increase in power with the P-1SC blower, but after we slipped the belt over the pulleys and set the blower hat over the carburetor, the engine instantly responded with 408 hp-a 49 percent jump in horsepower-and 423 lb-ft at 4,600 rpm. Clearly the stock cam and heads were holding this ProCharger back from making some big power. We had anticipated that, so the next step was to pitch the stock heads and roller cam and bolt on a set of RHS 180cc aluminum heads along with a healthy Comp Cams hydraulic roller cam. Two stories in one was the result here, because this swap alone was worth a solid power bump up to 392 hp at 6,200 rpm and a torque gain from 319 to 363 at 4,400. This created a decent 1,800-rpm powerband between peak torque and peak horsepower. We also ran into a little valve-float problem at 6,300 rpm, or the engine might have made even more power. We had a stout 43 percent increase in horsepower from a couple of simple bolt-ons.

With the blower back on, we preloaded the belt to minimize slipping it, and the ProCharger began building boost even at 3,000 rpm. The peak numbers are impressive with 605 hp and 520 lb-ft of torque out of a junkyard 302, but what's really cool is how effortlessly this came together. Remember, this is all on 91-octane pump gas. Adding a splash of 100-octane unleaded Rockett Brand Racing gas to the tank and upping the timing from 28 degrees to 32 degrees was worth 618 hp at the same 6,200 rpm with a total of 12 psi of boost. Clearly this little runner was willing to keep going with never a hint of problems with the short-block. The OE forged pistons obviously helped make this happen. We haven't done a leakdown test, but it would probably be beneficial to tear into the short-block and add rings and bearings. Then again, as strong as this motor runs, we're going to just leave it alone and beat on it some more. It's way too much fun.